A wireless, local area network (LAN) is a flexible data communications system that can either replace or extend a wired LAN to provide additional functionality. Using radio frequency (RF) technology, wireless-LANs transmit and receive data over the air, through walls, ceilings and even cement structures, without wired cabling. A wireless-LAN provides all the features and benefits of traditional LAN technologies, such as Ethernet and Token Ring, but without the limitation of being tethered to a cable. This provides greater freedom and increased flexibility.
In other words, a Wireless-LAN is a network in which a mobile user can connect to a local area network (LAN) through a wireless (radio) connection. A standard from the Institute of Electrical and Electronic Engineers (IEEE) 802.11B-1999, published Sep. 16, 1999 specifies the technologies for wireless-LANs. Accordingly, high bandwidth allocation for wireless-LANs will enable, at a relatively low cost, wiring of various buildings, such as classrooms, in the United States. One technique for providing high bandwidth allocation in a wireless-LAN is provided via ultra wide bandwidth (UWB) radio systems.
UWB radio systems employ the transmission of very short pulses of radio energy. These characteristic spectrum signatures extend across a wide range of radio frequencies. In addition, since UWB signals have high bandwidth and frequency diversity, UWB signals are particularly suited for high speed data communications in environments, such as indoors, where multi-path fading is likely. Consequently, UWB radio systems are generally well-suited for implementing a wireless-LAN.
Moreover, the radio spectrum utilized by wireless communication is considered to be fully utilized and, in fact, in short supply. In contrast, UWB signals, by their very nature, utilize spectrum already designed for other use and regulated by the Federal Communications Commission. Unlike continuous wave technologies that use sine waves to encode information, UWB technologies encode large amounts of information over short distances, using brief, extremely low power bursts or pulses of radio energy spread across a wide range of frequencies. As indicated above, one of the most appealing characteristics of UWB technology is its place in the frequency spectrum, a characteristic directly associated with low power consumption and interference immunity.
Accordingly, by transmitting data at a very low power, UWB devices are able to use spectrum already occupied by radio devices. This characteristic enables UWB technology to recycle spectrum, a characteristic of great value in a time when spectrum, a scarce resource, is in high technological demand. Unfortunately, wireless-LANs utilizing UWB radio signals may suffer from echoes due to multi-path fading. This problem becomes particularly serious when considering that a wireless-LAN must transmit signals and receive data over the air through walls, ceilings and even cement structures, without wired cable. As a result, transmission through such structures may cause echoes as the transmitted signals bounce off the walls.
Therefore, there remains a need to overcome one or more of the limitations in the above-described, existing art.